650 CATALOGUE OF DESTRUCTIVE EARTHQUAKES 



comparatively few in number, are fairly homogeneous in their 

 character. Secondly, the entries for recent times are com- 

 paratively numerous hut they are extremely heterogeneous. 

 References to cataclysms are lost amid long lists of mere earth 

 tremors. Efforts which have resulted in the creation or 

 extension of faults and the devastation of districts stand side 

 by side with references to "aftershocks" or slight adjustments 

 in the settlement of strata which may not have rattled a 

 window or awakened a sleeper. 



Although much time has been expended on the analyses of 

 these catalogues it is not surprising to find that the outcome 

 lias been more suggestive than definitive, and hut little has 

 been learned. 



The present Catalogue is an attempt to give a list of 

 earthquakes which have announced changes of geological im- 

 portance in the earth's crust ; movements which have probably 

 resulted in the creation or extension of a line of fault, the 

 vibrations accompanying which could, with proper instruments, 

 have been recorded over a continent or the whole surface of our 

 world. Small earthquakes have been excluded, while the 

 number of large earthquakes both for ancient and modern times 

 has been extended. As an illustration of exclusion, I may 

 mention that between 1800 and 180H, which are years taken at 

 random, I find in Mallet's catalogue 407 entries. Only 87 of 

 these, which were accompanied by structural damage, have been 

 retained. Other catalogues such as those of Perrey and Fuchs 

 have been treated similarly. 



The large catalogue of Count F. Montessus de Bailors, 

 stored in the library of the Geographical Society in Paris, 

 occupies 26 metres of bookshelves and contains about 140,000 

 entries. In the light of recent researches (see Geographical 

 Journal, Jan. 1910) which indicate that 30,000 earthquakes may 

 occur annually, the number of entries in the catalogue of 

 Montessus cannot be regarded as abnormal. If the seismicity 

 of the world has been constant during the last 1900 years, the 

 number of earthquakes which have taken place during this 

 period may have been 60,000,000. If we exclude small dis- 

 turbances, and only consider world-shaking earthquakes, which 

 at the present time take place at the rate of about 60 per year, 

 these would during the same interval have numbered some 

 100,000. The entries in the present Catalogue are less than 

 6,000. Several reasons for the smallness of this number 

 compared with what we should expect to find in a complete list, 

 have already been indicated. To these it must be added that 

 it has only been possible within the last few years to record 

 disturbances originating in oceanic beds and in uninhabited 

 regions. It is these instrumental records made during the last 

 10 years which have enabled me to give estimates of the total 

 number of large earthquakes occurring in the world per annum. 

 A list of earthquakes, each of which has been recorded over a 



